Exterior feed mechanism for automatic guns



y 3, 1967 F. P. REED ETAL EXTERIOR FEED MECHANISM FOR AUTOMATIC GUNS 5 Sheets-Sheet 1 Filed March 24, 1966 M mwv o x z i M ma vm M in .M mi 1 y 23, 1967 F. P. REED ETAL 3,320,855

EXTERIOR FEED MECHANISM FOR AUTOMATTC GUNS Filed March 24, 1966 5 Sheets-Sheet 2 INVENTORS Fr! Her'rik PIRam-B.

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ATTORNEY May 23, 1967 F. P. REED ETAL 3,320,855

EXTERIOR FEED MECHANISM FOR AUTOMATIC GUNS Filed March 24, 1966 5 Sheets-Sheet 3 INVENTORS Frnfleric'k P RII d I I1 J.L:'szzn.

ATTORN EY May 23, 1967 F. P. REED ETAL EXTERIOR FEED MECHANISM FOR AUTOMATIC GUNS Filed March 24, 1966 5 Sheets-Sheet 4 May 23, 1967 F. P. REED ETAL 3,320,855

EXTERIOR FILED MECHANISM F'Oh AU'E'(,IMAIH GUNS Filed March 24, 1966 5 Sheets-Sheet 5 FI L luvzu-rons Elma-rick 'P RII :3.

ATTORNEY United States Patent 3,320,855 EXTERIOR FEED MECIANSISM FOR AUTOMATIC UN Frederick P. Reed, Ludlow, and Albert J. Lizza, Wilbraham, Mass., assignors t0 the United States of America as represented by the Secretary of the Army Filed Mar. 24, 1966, Ser. No. 538,186

8 Claims. (CI. 89-11) This invention relates to machine guns which are fed with cartridges from a linked belt and pertains more particularly to feed mechanisms whereby the cartridges are stripped from the belt and moved to a battery position in the firearm receiver.

With those machine guns in which the basic action is translational and intermittent, the present feeding mechanisms draw the cartridge belt to the gun one pitch during only a portion of each operating cycle. Consequently, the movement of the belt is intermittent which places excessive strain upon the connected links because of the repeated rapid acceleration and deceleration to which the belt is subjected. These repeated accelerations and decelerations also cause the belt to whip which creates another serious problem in feeding.

It is therefore the principal object of this invention to provide for such machine guns a feeding mechanism whereby the cartridge belt is advanced at a constant velocity to reduce to a minimum all accelerative and decelerative forces produced therein and to prevent whipping of the cartridge belt.

It is a further object of this invention to provide such a feeding mechanism in which all motions are mechanically controlled and timed.

It is a further object of this invention to provide such a feeding mechanism which is perfectly synchronized to gun operation by being mechanically connected thereto and which is self-contained so as to be replaceable as a complete unit.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a side view of the feeding mechanism mounted to a machine gun;

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is a view taken along line 33 of FIG. 1;

FIG. 4 is an enlarged view showing the Geneva mechanism whereby continuous rotation of the driving wheel is converted to intermittent rotation of the driven wheel;

FIG. 5 is a view similar to FIG. 4 and further discloses the operation of the Geneva mechanism;

FIG. 6 is a view taken along line 66 of FIG. 2;

FIG. 7 is a view taken along line 7-7 of FIG. 6;

FIG. 8 is a view taken along line 8-8 of FIG. 1 and shows the pawl assembly in its retracted position;

FIG. 9 is a fragmentary view similar to FIG. 8 but shows the pawl assembly at the end of its driving stroke;

FIG. 10 is a view similar to FIG. 9 but shows the pawl displaced out of the way by the cartridge being moved to the mouth of the feeder housing; and

FIG. 11 is an enlarged perspective View of the pawl assembly and bell crank.

Shown in the figures is a machine gun 12 having a receiver 14 and a barrel 16 which is slidingly supported by the receiver for longitudinal reciprocation between a forward loading position and a rearward firing position. Barrel 16 is cylically actuated by an electrical drive motor 18 through a cam drum 20 such as is fully disclosed in patent application, Ser. No. 415,834, now Patent No. 3,241,448, filed Dec. 3, 1964, by John G. Rocha for Circuitous Cam Track With Crossovers and Follower Device Therefor and patent application, Ser. No. 434,717, filed Feb. 23, 1965, now Patent No. 3,296,930, by John G. Rocha for Clutch-Lock for Externally Powered Firearm Feeding Mechanism.

Cartridges 22 are successively fed to a battery position in receiver 14 for engulfment by barrel 16, when in its firing position, by a separate self-contained feeding mechanism 24. Feeding mechanism 24 is fixedly mounted on a base 26 and receiver 14 is resiliently mounted thereon for limited longitudinal displacement so that little of the recoil displacement of the receiver by discharge forces is transferred to the feeding mechanism. During the feeding cycle, when a cartridge 22 is transferred by feeding mechanism 24 into receiver 14, the receiver is releasably seared to base 26, so as to be immovable relative to feeding mechanism 24, as disclosed by patent application, Ser. No. 470,942, filed July 9, 1965, by Frederick P. Reed for Machine Gun With a Mount for Reducing the Recoil Forces Applied to the Trunnions.

Feeding mechanism 24 includes a housing 28 and a pair of sprocket wheels 30 which are located therein and which are mounted on a shaft 32 for rotation thereby. Shaft 32 is connected to drive motor 18 through a gear box 34 which is designed so that sprocket wheels 30 are rotated one pitch for each cyclic displacement of barrel 16.

Housing 28 is provided on opposite sides with an entrance port 36 and an exit port 38 for passage of a cartridge belt 39 through the housing along the top thereof as shown in FIG. 8. Cartridge belt 39 is comprised of a plurality of releasably connected links 40 which are respectively adapted to grip a cartridge 22 for forward removal therefrom. Each of links 40 is provided with a pair of oppositely extending tabs 42 arranged for sliding engagement with a pair of longitudinally spaced rails 44 which extend along the top of housing 28 so that the links are slidable between entrance port 36 and exit port 38 and are held against longitudinal displacement when cartridges 22 are stripped forwardly therefrom.

Cartridges 22 are stripped from their respective links while moving along rails 44 by a pair of longitudinally spaced, prong type strippers 46 which also serve to guide the stripped cartridges to an arcuate ramp 47 which leads to a mouth 48 located in housing 28 above the battery position in receiver 14. Cartridges 22 are moved along strippers 46 and ramp 47 by sprocket wheels 30 and the ramp is designed, as shown in FIG. 8, so that as the cartridges approach mouth 48 they are gradually moved radially away from the axis of the sprocket wheels. When a cartridge 22 reaches mouth 48 it is free of sprocket wheels 30 and it is held in the mouth by the pushing one of the sprockets 49 when passing thereover. Cartridge 22 is releasably retained in mouth 48 by a pair of springbiased plungers 50 located on each side thereof. When plungers 50 are pressed outwardly to their normal positions, the distance between corresponding ones thereof, on opposite sides of mouth 48, is less than the diameter of the contacted sections of cartridge 22. When pressure is applied downwardly against cartridge 22 in mouth 48, the arcuate configuration of the cartridge cammingly presses the plungers 50 inwardly to permit passage of the cartridge thereby to battery position.

Cartridge 22 in mouth 48 is pressed downwardly to battery position by a feed pawl device 52 which includes a pawl assembly 54 slidingly mounted on a vertically disposed rod 56, a bell crank 58 pivotally mounted on a longitudinally disposed pin 60, a crank 59 and a Geneva mechanism 62 which cooperates with the bell crank and crank to convert continuous rotation of shaft 32 to intermittent reciprocation of the pawl assembly, as hereinafter described.

Pawl assembly 54 includes a slide 64 which is slidingly mounted on rod 56 and a pawl 66 which is pivotally mounted on the slide by means of a shaft 68. A spring 70 is disposed between slide 64 and pawl 66 to resiliently hold the pawl in a normal position wherein pusher arm portion 72 thereof is vertically disposed, as shown in FIGS. 8 and 9, in position for displacing the mouthpositioned-cartridge 22 downwardly to battery position when pawl assembly 54 is actuated downwardly on rod 56. Pawl 66 is arranged on slide 64 so as to be pivotal away from normal position in a counterclockwise direction, as shown in FIG. 10, which is the direction of rotation of sprocket wheels 30, whereby the pawl is displaced out of the way by the cartridge 22 being moved into mouth 48. Pawl 66 cooperates with a pair of radially spaced supports 74 in receiver 14 as shown in FIG. 9, for securely holding cartridge 22 in battery position ready for envelopment by barrel 16 when displaced to the firing position.

Referring to FIGS. 2-7, Geneva mechanism 62 is seen to include a driving wheel 76 mounted on shaft 32 for rotation thereby and a driven wheel 78. Sprocket wheels 30 are each provided with eight sprockets 49 and driving wheel 76 is correspondingly provided with eight ear portions 80 extending radially and symmetrically from the perimeter thereof. Formed in each of the ears 80 is a cam path 82 which during rotation of driving wheel 76 engages one of three pins 84 which extend outwardly from driven wheel 78 and which are symmetrically dis-,

posed therein. Cam path 82 is formed so that during passage thereof over the engaged one of the pins 84 driven wheel 78 is rotated 120. Extending between pairs of the ears 80 is an arcuate perimeter section 86 which slidingly contacts the one of the pins 84 which has passed through cam path 82 and the next succeeding one to hold driven wheel 78 against further rotation and the succeeding one of the pins in position for entry into the cam path in the next succeeding ear. Thus, during one rotation of driving wheel 76, driven wheel 78 is intermittently rotated eight times 120.

Each 120 rotation of driven wheel 78 is converted to one cyclic displacement of pawl assembly downwardly and upwardly in driving and retraction strokes, through the cooperation of bell crank 58 and crank 59 therewith as hereinafter described. Crank 59 includes a crankshaft 88 on which there is fixed a gear 90 which is in meshed engagement with a ring gear 92 formed around the perimeter of driven wheel 78 and such gears are designed so that 120 rotation of the driven wheel rotates gear 90 one complete revolution. Mounted on the other end of crankshaft 88, as shown in FIG. 6, is a disc 94 from which there extends a crankpin 96.

Referring to FIGS. 8-10, crankpin 96 is seen to be received by a channel 98 formed in one arm of hell crank 58 so that rotation of crank 59 one cycle is converted to a cyclic displacement of the bell crank. The other arm of bell crank 58 is bifurcated to form a pair of arms 100 which receive pawl 66 therebetween and such arms are each provided with an elongated slot 102 which receives one of the extending ends of shaft 68 whereby pivotal displacement of the bell crank is converted to translational reciprocation of pawl assembly 54 downwardly and upwardly on rod 56 in driving and retraction strokes. It is obvious that by changing the relationships of channel 98 with crank 59 the velocity of the driving stroke can be changed respective to the velocity of the retraction stroke.

Operation During operation of machine gun 12, feeding mechanism 24 is driven by the same drive motor 18 which drives the machine gun so as to be positively synchronized therewith at all rates of fire. For every cyclic reciprocation of barrel 16, which determines the firing rate of machine gun 12, sprocket wheels 30 are rotated to advance cartridge belt 39 one pitch and locate a fresh cartridge 22 at mouth 48. As sprocket wheels 30 are rotated, driving wheel 76 is rotated therewith to move cam path 82 in one of the cars along one of the pins 84 in driven wheel 78 so that such driven wheel is rotated 120.

Rotation of driven wheel 78 120 is multipled to one complete rotation of crank 59 through the relationship of gear with ring gear 92 and this moves crankpin 96 backwards and forward along channel 98 so that bell crank 58 is reciprocally pivoted one complete cycle. Pivotal displacement of hell crank 58 actuates feed pawl assembly 54 downwardly and upwardly on rod 56 in driving and retraction strokes. The driving stroke is arranged to commence when a cartridge 22 is located in mouth 48 and is being held therein by previously pushing one of the sprockets 49. As feed pawl assembly 54 moves downwardly, cartridge 22 in mouth 48 is pressed thereby past plungers 50 to battery position and at the end of the drive stroke such cartridge 22 is held at three points by supports 74 and pawl 66 ready for engulfment by barrel 16 when moving to firing position.

During the retraction stroke of pawl assembly 54, pawl 66 is pivoted out of the way by cartridge 22 being moved to mouth 48. After passage of the end of pawl 66 by the incoming cartridge 22, it is biased back to its normal position by spring 70.

From the foregoing it is clearly apparent that there is provided herein for machine guns in which the basic action is translational reciprocation, an improved feeding mechanism whereby the cartridge belt is advanced at a constant velocity to reduce to a minimum the trains applied thereto and which is perfectly synchronized to the firing rate of the gun.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

We claim:

1. In combination with a machine gun having a receiver and a drive motor for operating the machine gun, a separate feeding mechanism for feeding cartridges successively to a battery position in the receiver including a housing replaceably mounted on the receiver, a mouth located in said housing for passage of the cartridge there from to the battery position, means for delivering the cartridges successively to said mouth, a feed pawl device arranged for pressing the cartridges in said mouth therethrough to the battery position, a bell crank for actuating said feed pawl device and a Geneva mechanism and a cooperating crank disposed between the drive motor and said bell crank for intermittently displacing said feed pawl in synchronization with the operation of the machine gun.

2. The combination as defined in claim 1 wherein said drive motor is of continuous rotary type, and said feed pawl device includes a rod and a pawl assembly mounted for translational displacement on said rod against the one of the cartridges in said mouth for radial displacement therethrough to the battery position.

3. The combination as defined in claim 1 wherein said means for delivering the cartridges successively to said mouth includes a sprocket wheel and ramp means arranged to gradually move said cartridges clear of said sprocket wheel when approaching said mouth.

4. The combination as defined in claim 1 and including spring-biased plungers mounted in said housing at said mouth to releasably retain the cartridges therein until pressed therethrough by said feed pawl device.

5. In combination with a machine gun having a base, a receiver resiliently mounted on the base for longitudinal displacement responsive to recoil forces produced by operation of the machine gun, a barrel slidingly supported by the receiver for translational and intermittent displacement to and from a firing position and a rotary drive motor arranged for cyclically displacing the barrel; a feeding mechanism including a housing fixedly mounted on said base, a sprocket wheel mounted in said housing for rotation by said drive motor for continuously moving a cartridge belt including a plurality of linked cartridges through said housing, strippers for removing the cartridges from the cartridge belt, a pawl feed device mounted in said housing for moving the stripped cartridges radially therefrom to a battery position in the receiver for envelopment by the barrel when displaced to the firing position, and means for intermittently actuating said pawl teed device in synchronization with the actuation of the barrel without interrupting rotation of the sprocket wheel.

6. The combination as defined in claim 5 wherein said feed pawl device includes a pawl assembly slidingly mounted on a rod for translational displacement thereon and said means include a Geneva mechanism for converting continuous rotation of said drive motor to an intermittent rotary movement, a crank connected to said Geneva mechanism for intermittent rotation thereby, and a bell crank operationally disposed between said crank and said pawl assembly for converting intermittent rotation of said crank to intermittent translational movement of said pawl assembly.

7. The combination as defined in claim 6 wherein said sprocket wheel is fixedly mounted on a shaft driven by said drive motor and includes a specific number of sprockets and said Geneva mechanism includes a driven wheel including three pins extending therefrom in symmetrical arrangement, a driving wheel fixedly mounted on said shaft, a plurality of ears equal to the number of said sprockets extending symmetrically around the perimeter of said driving wheel, an arcuate perimeter section formed between pairs of said cars, a cam path formed in each of said cars so as to extend from said perimeter section on one side thereof to said perimeter section on the other side, said cam path being arranged to receive one of said pins during rotation of said driving wheel and to rotate said driven wheel during passage of said cam path over the engaged one of said pins and each of said perimeter sections being arranged to slidingly contact pairs of said pins after each intermittent rotation of said driven wheel to secure said driven wheel against rotation and align the next one of said pins with the following one of said cam paths.

8. The combination as defined in claim 7 and including cooperating gear means on said Geneva mechanism and said crank for multiplying the 120 rotation of said driven wheel to one complete rotation of said crank.

No references cited.

SAMUEL FEINBERG, Primary Examiner.

S. C. BENTLEY, Assistant Examiner. 

1. IN COMBINATION WITH A MACHINE GUN HAVING A RECEIVER AND A DRIVE MOTOR FOR OPERATING THE MACHINE GUN, A SEPARATE FEEDING MECHANISM FOR FEEDING CARTRIDGES SUCCESSIVELY TO A BATTERY POSITION IN THE RECEIVER INCLUDING A HOUSING REPLACEABLY MOUNTED ON THE RECEIVER, A MOUTH LOCATED IN SAID HOUSING FOR PASSAGE OF THE CARTRIDGE THEREFROM TO THE BATTERY POSITION, MEANS FOR DELIVERING THE CARTRIDGES SUCCESSIVELY TO SAID MOUTH, A FEED PAWL DEVICE ARRANGED FOR PRESSING THE CARTRIDGES IN SAID MOUTH THERETHROUGH TO THE BATTERY POSITION, A BELL CRANK FOR ACTUATING SAID FEED PAWL DEVICE AND A GENEVA MECHANISM AND A COOPERATING CRANK DISPOSED BETWEEN THE DRIVE MOTOR AND SAID BELL CRANK FOR INTERMITTENTLY DISPLACING SAID FEED PAWL IN SYNCHRONIZATION WITH THE OPERATION OF THE MACHINE GUN. 